title: Genomic DNA damage and ATR-Chk1 signaling determine oncolytic adenoviral efficacy in human ovarian cancer cells.
abstract: Oncolytic adenoviruses replicate selectively within and lyse malignant cells. As such, they are being developed as anticancer therapeutics. However, the sensitivity of ovarian cancers to adenovirus cytotoxicity varies greatly, even in cells of similar infectivity. Using both the adenovirus E1A-CR2 deletion mutant dl922-947 and WT adenovirus serotype 5 in a panel of human ovarian cancer cell lines that cover a 3-log range of sensitivity, we observed profound overreplication of genomic DNA only in highly sensitive cell lines. This was associated with the presence of extensive genomic DNA damage. Inhibition of ataxia telangiectasia and Rad3-related checkpoint kinase 1 (ATR-Chk1), but not ataxia telangiectasia mutated (ATM), promoted genomic DNA damage and overreplication in resistant and partially sensitive cells. This was accompanied by increased adenovirus cytotoxicity both in vitro and in vivo in tumor-bearing mice. We also demonstrated that Cdc25A was upregulated in highly sensitive ovarian cancer cell lines after adenovirus infection and was stabilized after loss of Chk1 activity. Knockdown of Cdc25A inhibited virus-induced DNA damage in highly sensitive cells and blocked the effects of Chk1 inhibition in resistant cells. Finally, inhibition of Chk1 decreased homologous recombination repair of virus-induced genomic DNA double-strand breaks. Thus, virus-induced host cell DNA damage signaling and repair are key determinants of oncolytic adenoviral activity, and promoting unscheduled DNA synthesis and/or impeding homologous recombination repair could potentiate the effects of oncolytic adenoviruses in the treatment of ovarian cancer.
authors.affiliation: Centre for Molecular Oncology and Imaging, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom.
authors.forename: Claire M
authors.initials: CM
authors.lastname: Connell
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shibata
authors.forename: Laura A
authors.initials: LA
authors.lastname: Tookman
authors.forename: Kyra M
authors.initials: KM
authors.lastname: Archibald
authors.forename: Magdalena B
authors.initials: MB
authors.lastname: Flak
authors.forename: Katrina J
authors.initials: KJ
authors.lastname: Pirlo
authors.forename: Michelle
authors.initials: M
authors.lastname: Lockley
authors.forename: Sally P
authors.initials: SP
authors.lastname: Wheatley
authors.forename: Iain A
authors.initials: IA
authors.lastname: McNeish
mesh_terms: D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D004249:DNA Damage; D004260:DNA Repair; D004261:DNA Replication; D005260:Female; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009154:Mutation; D009368:Neoplasm Transplantation; D050130:Oncolytic Virotherapy; D050504:Oncolytic Viruses / Q000235:genetics* / Q000502:physiology*; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D014183:Transplantation, Heterologous; D020687:cdc25 Phosphatases / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D011494:Protein Kinases; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C000605869:Chek1 protein, mouse; D017346:Protein Serine-Threonine Kinases; C517004:CDC25A protein, human; D020687:cdc25 Phosphatases